RandomNumberGenerator C#

using System;
using System.Security.Cryptography;

public static string GenerateSecureToken(int size = 16)
{
    byte[] randomBytes = new byte[size];
    RandomNumberGenerator.Fill(randomBytes);
    return Convert.ToBase64String(randomBytes);
}

Imports System
Imports System.Security.Cryptography

Public Shared Function GenerateSecureToken(Optional ByVal size As Integer = 16) As String
	Dim randomBytes(size - 1) As Byte
	RandomNumberGenerator.Fill(randomBytes)
	Return Convert.ToBase64String(randomBytes)
End Function

using IronPdf;
using IronPdf.Editing;
using System;
using System.Security.Cryptography;

class Program
{
    public static void Main(string[] args)
    {
        // Create an instance of Program to run non-static methods
        var program = new Program();
        program.CreateEncryptedPdf();
    }

    string GenerateSecurePassword(int length = 12)
    {
        const string chars = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789!@#$%^&*()";
        byte[] data = new byte[length];
        RandomNumberGenerator.Fill(data);

        char[] result = new char[length];
        for (int i = 0; i < length; i++)
        {
            result[i] = chars[data[i] % chars.Length];
        }
        return new string(result);
    }

    void CreateEncryptedPdf()
    {
        string password = GenerateSecurePassword();

        var renderer = new ChromePdfRenderer();
        var pdf = renderer.RenderHtmlAsPdf("<h1>Confidential PDF</h1><p>Access is restricted.</p>");

        // Set security settings
        pdf.SecuritySettings.UserPassword = password;
        pdf.SecuritySettings.AllowUserAnnotations = false;
        pdf.SecuritySettings.AllowUserCopyPasteContent = false;
        pdf.SecuritySettings.AllowUserPrinting = IronPdf.Security.PdfPrintSecurity.NoPrint;

        string filePath = "EncryptedSecurePdf.pdf";
        pdf.SaveAs(filePath);

        Console.WriteLine($"Encrypted PDF saved to {filePath} with password: {password}");
    }
}

Imports IronPdf
Imports IronPdf.Editing
Imports System
Imports System.Security.Cryptography

Friend Class Program
	Public Shared Sub Main(ByVal args() As String)
		' Create an instance of Program to run non-static methods
'INSTANT VB NOTE: The variable program was renamed since it may cause conflicts with calls to static members of the user-defined type with this name:
		Dim program_Conflict As New Program()
		program_Conflict.CreateEncryptedPdf()
	End Sub

	Private Function GenerateSecurePassword(Optional ByVal length As Integer = 12) As String
		Const chars As String = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789!@#$%^&*()"
		Dim data(length - 1) As Byte
		RandomNumberGenerator.Fill(data)

		Dim result(length - 1) As Char
		For i As Integer = 0 To length - 1
			result(i) = chars.Chars(data(i) Mod chars.Length)
		Next i
		Return New String(result)
	End Function

	Private Sub CreateEncryptedPdf()
		Dim password As String = GenerateSecurePassword()

		Dim renderer = New ChromePdfRenderer()
		Dim pdf = renderer.RenderHtmlAsPdf("<h1>Confidential PDF</h1><p>Access is restricted.</p>")

		' Set security settings
		pdf.SecuritySettings.UserPassword = password
		pdf.SecuritySettings.AllowUserAnnotations = False
		pdf.SecuritySettings.AllowUserCopyPasteContent = False
		pdf.SecuritySettings.AllowUserPrinting = IronPdf.Security.PdfPrintSecurity.NoPrint

		Dim filePath As String = "EncryptedSecurePdf.pdf"
		pdf.SaveAs(filePath)

		Console.WriteLine($"Encrypted PDF saved to {filePath} with password: {password}")
	End Sub
End Class